This invention relates to check valves such as check valves used for air conditioner system charging valves, and in particular to an improved check valve having a quick lock attachment feature that reduces or eliminates the need for threaded connections in the valve itself.
U.S. Pat. No. 4,979,721, assigned to the assignee of the present invention, discloses one prior art check valve which has been used successfully in air conditioning charging systems. This valve has been fabricated from metals such as aluminum and brass, and includes a two part assembly made up of a lower portion that defines a braze port and an upper portion in which a reciprocating valve pin is mounted. The upper and lower portions are held together by a threaded connection. In use, the lower portion is installed in an air conditioner line, preferably by brazing it in place. The upper portion is then threaded in place to the lower portion to complete the assembly.
Though this valve has met with considerable commercial success, there is a continuing need for check valves which are lighter in weight and lower in cost. Furthermore, under certain operating conditions the threads used in this valve to hold the upper and lower portions of the housing together may gall, or the threads of the lower portion may otherwise be damaged. When this happens, the lower portion must be replaced, and this requires brazing steps which are undesirable in many settings.
Accordingly, it is an object of this invention to provide an improved check valve which is quick to assemble, low in cost, light in weight, and which avoids the use of threads in the lower portion of the housing and the problems associated therewith.